Fix mistake in XML component system

Use argument value instead of argument type, previously the
component system would instantiate

<component name="Foo" args="blah: String">
    <p>{blah}</p>
</component>

<Foo blah="Test"/>

with "<p>String</p>" instead of: "<p>Test</p>".

azul/xml.rs

@@ -577,7 +577,7 @@ fn validate_and_filter_component_args(xml_attributes: &XmlAttributeMap, valid_ar
     for (xml_attribute_name, xml_attribute_value) in xml_attributes.iter() {
 
         let arg_value = match valid_args.get(xml_attribute_name) {
-            Some(s) => Some(s),
+            Some(valid_arg_type) => Some(xml_attribute_value),
             None => {
                 if DEFAULT_ARGS.contains(&xml_attribute_name.as_str()) {
                     None // no error, but don't insert the attribute name

examples/xml/ui.xml

@@ -1,8 +1,15 @@
-<app>
-  <div id="wrapper">
-    <div id="overflowing_1"></div>
-    <div id="overflowing_2">
-      <div id="overflowing_3"></div>
+<component name="MenuBarLabel" args="menu_name: String">
+    <div class="menubar_label_container">
+        <p class="menubar_label">{menu_name}</p>
+    </div>
+</component>
+
+<component name="MenuBar">
+    <div class="menubar_container">
+        <MenuBarLabel menu_name="Test"/>
     </div>
-  </div>
+</component>
+
+<app>
+  <MenuBar />
 </app>

examples/xml/xml.css

@@ -1,46 +0,0 @@
-* {
-    border: 1px solid black;
-    box-sizing: border-box;
-    border-radius: 10px;
-}
-
-#wrapper {
-    top: 50px;
-    left: 50px;
-    width: 400px;
-    height: 400px;
-    background: green;
-    overflow: scroll;
-}
-
-#overflowing_1 {
-    position: absolute;
-    top: 200px;
-    left: 40px;
-    width: 40px;
-    height: 40px;
-    background: red;
-}
-
-#overflowing_2 {
-    position: absolute;
-    top: 290px;
-    left: 40px;
-    width: 40px;
-    height: 40px;
-    background: blue;
-    overflow: visible;
-}
-
-#overflowing_3 {
-    position: absolute;
-    width: 40px;
-    height: 40px;
-    top: 100px;
-    left: 100px;
-    background: yellow;
-}
-
-#overflowing_3:hover {
-    background-color: red;
-}